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authorLance Stout <lancestout@gmail.com>2011-03-24 12:25:17 -0400
committerLance Stout <lancestout@gmail.com>2011-03-24 12:25:17 -0400
commit6d45971411f88f134abc28051c678986db8e9df8 (patch)
treea7e71c34ef8e539b262249f3bcc514975c314332 /sleekxmpp
parent84e2589f2205eb0b88fca92418c17950ab3a3f1b (diff)
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Allow a stanza plugin to override a parent's interfaces.
Each interface, say foo, may be overridden in three ways: set_foo get_foo del_foo To declare an override in a plugin, add the class field overrides as so: overrides = ['set_foo', 'del_foo'] Each override must have a matching set_foo(), etc method for implementing the new behaviour. To enable the overrides for a particular parent stanza, pass the option overrides=True to register_stanza_plugin. register_stanza_plugin(Stanza, Plugin, overrides=True) Example code: class Test(ElementBase): name = 'test' namespace = 'testing' interfaces = set(('foo', 'bar')) sub_interfaces = set(('bar',)) class TestOverride(ElementBase): name = 'test-override' namespace = 'testing' plugin_attrib = 'override' interfaces = set(('foo',)) overrides = ['set_foo'] def setup(self, xml): # Don't include an XML element in the parent stanza # since we're adding just an attribute. # If adding a regular subelement, no need to do this. self.xml = ET.Element('') def set_foo(self, value): print("overrides!") self.parent()._set_attr('foo', 'override-%s' % value) register_stanza_plugin(Test, TestOverride, overrides=True) Example usage: >>> t = TestStanza() >>> t['foo'] = 'bar' >>> t['foo'] 'override-bar'
Diffstat (limited to 'sleekxmpp')
-rw-r--r--sleekxmpp/xmlstream/stanzabase.py102
1 files changed, 77 insertions, 25 deletions
diff --git a/sleekxmpp/xmlstream/stanzabase.py b/sleekxmpp/xmlstream/stanzabase.py
index 860f8d13..b8a7ceaa 100644
--- a/sleekxmpp/xmlstream/stanzabase.py
+++ b/sleekxmpp/xmlstream/stanzabase.py
@@ -24,24 +24,32 @@ log = logging.getLogger(__name__)
XML_TYPE = type(ET.Element('xml'))
-def register_stanza_plugin(stanza, plugin, iterable=False):
+def register_stanza_plugin(stanza, plugin, iterable=False, overrides=False):
"""
Associate a stanza object as a plugin for another stanza.
Arguments:
- stanza -- The class of the parent stanza.
- plugin -- The class of the plugin stanza.
- iterable -- Indicates if the plugin stanza
- should be included in the parent
- stanza's iterable 'substanzas'
- interface results.
+ stanza -- The class of the parent stanza.
+ plugin -- The class of the plugin stanza.
+ iterable -- Indicates if the plugin stanza should be
+ included in the parent stanza's iterable
+ 'substanzas' interface results.
+ overrides -- Indicates if the plugin should be allowed
+ to override the interface handlers for
+ the parent stanza.
"""
tag = "{%s}%s" % (plugin.namespace, plugin.name)
stanza.plugin_attrib_map[plugin.plugin_attrib] = plugin
stanza.plugin_tag_map[tag] = plugin
if iterable:
+ # Prevent weird memory reference gotchas.
stanza.plugin_iterables = stanza.plugin_iterables.copy()
stanza.plugin_iterables.add(plugin)
+ if overrides:
+ # Prevent weird memory reference gotchas.
+ stanza.plugin_overrides = stanza.plugin_overrides.copy()
+ for interface in plugin.overrides:
+ stanza.plugin_overrides[interface] = plugin.plugin_attrib
# To maintain backwards compatibility for now, preserve the camel case name.
@@ -130,6 +138,11 @@ class ElementBase(object):
subitem -- A set of stanza classes which are allowed to
be added as substanzas. Deprecated version
of plugin_iterables.
+ overrides -- A list of interfaces prepended with 'get_',
+ 'set_', or 'del_'. If the stanza is registered
+ as a plugin with overrides=True, then the
+ parent's interface handlers will be
+ overridden by the plugin's matching handler.
types -- A set of generic type attribute values.
tag -- The namespaced name of the stanza's root
element. Example: "{foo_ns}bar"
@@ -139,6 +152,10 @@ class ElementBase(object):
associated plugin stanza classes.
plugin_iterables -- A set of stanza classes which are allowed to
be added as substanzas.
+ plugin_overrides -- A mapping of interfaces prepended with 'get_',
+ 'set_' or 'del_' to plugin attrib names. Allows
+ a plugin to override the behaviour of a parent
+ stanza's interface handlers.
plugin_tag_map -- A mapping of plugin stanza tag names with
the associated plugin stanza classes.
is_extension -- When True, allows the stanza to provide one
@@ -204,7 +221,9 @@ class ElementBase(object):
interfaces = set(('type', 'to', 'from', 'id', 'payload'))
types = set(('get', 'set', 'error', None, 'unavailable', 'normal', 'chat'))
sub_interfaces = tuple()
+ overrides = {}
plugin_attrib_map = {}
+ plugin_overrides = {}
plugin_iterables = set()
plugin_tag_map = {}
subitem = set()
@@ -380,12 +399,13 @@ class ElementBase(object):
The search order for interface value retrieval for an interface
named 'foo' is:
1. The list of substanzas.
- 2. The result of calling get_foo.
- 3. The result of calling getFoo.
- 4. The contents of the foo subelement, if foo is a sub interface.
- 5. The value of the foo attribute of the XML object.
- 6. The plugin named 'foo'
- 7. An empty string.
+ 2. The result of calling the get_foo override handler.
+ 3. The result of calling get_foo.
+ 4. The result of calling getFoo.
+ 5. The contents of the foo subelement, if foo is a sub interface.
+ 6. The value of the foo attribute of the XML object.
+ 7. The plugin named 'foo'
+ 8. An empty string.
Arguments:
attrib -- The name of the requested stanza interface.
@@ -395,6 +415,16 @@ class ElementBase(object):
elif attrib in self.interfaces:
get_method = "get_%s" % attrib.lower()
get_method2 = "get%s" % attrib.title()
+
+ if self.plugin_overrides:
+ plugin = self.plugin_overrides.get(get_method, None)
+ if plugin:
+ if plugin not in self.plugins:
+ self.init_plugin(plugin)
+ handler = getattr(self.plugins[plugin], get_method, None)
+ if handler:
+ return handler()
+
if hasattr(self, get_method):
return getattr(self, get_method)()
elif hasattr(self, get_method2):
@@ -429,13 +459,14 @@ class ElementBase(object):
The effect of interface value assignment for an interface
named 'foo' will be one of:
1. Delete the interface's contents if the value is None.
- 2. Call set_foo, if it exists.
- 3. Call setFoo, if it exists.
- 4. Set the text of a foo element, if foo is in sub_interfaces.
- 5. Set the value of a top level XML attribute name foo.
- 6. Attempt to pass value to a plugin named foo using the plugin's
+ 2. Call the set_foo override handler, if it exists.
+ 3. Call set_foo, if it exists.
+ 4. Call setFoo, if it exists.
+ 5. Set the text of a foo element, if foo is in sub_interfaces.
+ 6. Set the value of a top level XML attribute name foo.
+ 7. Attempt to pass value to a plugin named foo using the plugin's
foo interface.
- 7. Do nothing.
+ 8. Do nothing.
Arguments:
attrib -- The name of the stanza interface to modify.
@@ -445,6 +476,16 @@ class ElementBase(object):
if value is not None:
set_method = "set_%s" % attrib.lower()
set_method2 = "set%s" % attrib.title()
+
+ if self.plugin_overrides:
+ plugin = self.plugin_overrides.get(set_method, None)
+ if plugin:
+ if plugin not in self.plugins:
+ self.init_plugin(plugin)
+ handler = getattr(self.plugins[plugin], set_method, None)
+ if handler:
+ return handler(value)
+
if hasattr(self, set_method):
getattr(self, set_method)(value,)
elif hasattr(self, set_method2):
@@ -480,12 +521,13 @@ class ElementBase(object):
The effect of deleting a stanza interface value named foo will be
one of:
- 1. Call del_foo, if it exists.
- 2. Call delFoo, if it exists.
- 3. Delete foo element, if foo is in sub_interfaces.
- 4. Delete top level XML attribute named foo.
- 5. Remove the foo plugin, if it was loaded.
- 6. Do nothing.
+ 1. Call del_foo override handler, if it exists.
+ 2. Call del_foo, if it exists.
+ 3. Call delFoo, if it exists.
+ 4. Delete foo element, if foo is in sub_interfaces.
+ 5. Delete top level XML attribute named foo.
+ 6. Remove the foo plugin, if it was loaded.
+ 7. Do nothing.
Arguments:
attrib -- The name of the affected stanza interface.
@@ -493,6 +535,16 @@ class ElementBase(object):
if attrib in self.interfaces:
del_method = "del_%s" % attrib.lower()
del_method2 = "del%s" % attrib.title()
+
+ if self.plugin_overrides:
+ plugin = self.plugin_overrides.get(del_method, None)
+ if plugin:
+ if plugin not in self.plugins:
+ self.init_plugin(plugin)
+ handler = getattr(self.plugins[plugin], del_method, None)
+ if handler:
+ return handler()
+
if hasattr(self, del_method):
getattr(self, del_method)()
elif hasattr(self, del_method2):